The shafts look knurled, so Im sure you could add some knobs of your choice.

Of course one could add knob. But the shafts seem very close to one another, so that would likely reduce the fingerspace between them.
Now, it's not like this is a huge dealbreaker, just a minor annoyance I guess.

As much as one can hear that through a youtube video played over not-so-great desktop speaker, it does sound kinda clean. Whch might be good or bad.
I'd rather had some proper knobs on this thing, but I guess we all like our Volcas, don't we? And this might fit nicely next to one.